No abstract

Natural electric field variations are measured at the sea bottom over long periods of time by means of stationary, vertical, and horizontal galvanic antennas. We compare the power spectra of the vertical and horizontal field components and the extent to which they may be reduced by standard averaging techniques. Although the raw spectra of the vertical and horizontal components do not differ greatly, the difference in the spectra after averaging is significantly greater. Most significantly, in the frequency range between 0.0005 and 0.03 Hz, this averaging scheme suppresses the vertical electric field component more strongly than the horizontal component.

The natural E-field variations measured at the sea bottom, and the magnitude of the different field components compared in the light of the theory for induction caused by ocean surface waves. At shallow sea depths of 107–122 meters only the vertical component carries an observable effect of ocean waves, whereas the horizontal field is dominated by the larger magnetotelluric noise. This agrees well with theoretical predictions.

The goal of the PolarquEEEst experiment was to measure the cosmic charged particle rate at latitudes greater than 66$$^{\circ }$$∘ N, where no systematic and accurate measurements at sea level have ever been performed. A latitude range well above the Arctic Circle was explored on board of a sailboat, up to the unprecedented northernmost value of $$82^{\circ }07^{\prime }$$82∘07′ N. In this paper a description of the experimental set-up is reported, then the procedures for calibration and data analysis are described in detail. The results show that the rate measured in this latitude range stays constant within a novel accuracy of $$\pm 1$$±1%.